1. Field of the Invention
The present invention relates to a tape cassette for use with a magnetic recording and/or reproducing apparatus. Particularly, the present invention relates to a tape cassette having front and rear lids for protecting a loaded magnetic tape against dust and having its rear lid suspended from the front lid by means of a connecting lever.
2. Description of the Related Art
A tape cassette to be used with a magnetic recording and/or reproducing apparatus such as a video tape recorder is exemplified by a VHS standard tape cassette having a tape width of 1/2 inch, or by an 8 mm tape cassette having a tape width of 8 mm, as is well known in the prior art.
FIG. 1(A) is a perspective view of the VHS standard tape cassette, and FIG. 1(B) is a side view for explaining a lid opening action of the VHS standard tape cassette.
A VHS tape cassette 100, as shown in FIGS. 1(A) and 1(B), is assembled from an upper half member 101 and a lower half member 102 into a box-shaped casing. This VHS standard tape cassette 100 is used to perform recording and/or reproducing operations by not-shown magnetic recording and/or reproducing apparatuses. For these operations, the VHS standard tape cassette 100 has its external size and shape generally standardized to keep interchangeability with the apparatus.
Moreover, a magnetic tape T is made to move between a supply reel 103 and a take-up reel 104, which are disposed in the VHS standard tape cassette 100. The magnetic tape T wound on the supply reel 103 is guided around a supply side guide pole 105 and along a front lid 106 disposed at openings 102a of the lower half member 102 and is guided around a take-up side guide pole 107 so as to be taken-up on the take-up reel 104.
The openings 102a of the lower half member 102 is opened at its bottom for permitting tape loading members (not-shown) of the apparatus.
On the other hand, the front lid 106 is provided for protecting the magnetic face of the magnetic tape T against dust and finger-prints or the like. This front lid 106 is so supported at the right-hand and left-hand sides of the tape cassette 100 that it can be opened or closed on a pair of pins 106a and 106a (although only one is shown) integrated with the inner side of the right-hand and left-hand sides of the front lid 106. However, the front lid 106 is retained and closed by a front lid lock member 108 disposed at the left-hand side of the tape cassette 100.
Referring to FIG. 1(B), only when the VHS standard tape cassette 100 is inserted into the (not-shown) magnetic recording and/or reproducing apparatus, the front lid lock member 108 is released by a lid opening device of the apparatus so that the front lid 106 is opened on the pins 106a formed on the front lid 106, as indicated by double-dotted lines. At this time, an opening angle .theta..sub.1 of the front lid 106 is not so large for a small-sized, lightweight portable apparatus but is sufficiently large for a large-sized tape deck or professional-use apparatus.
With the front lid 106 being opened, the apparatus is loaded with the magnetic tape T along its predetermined tape path by the (not-shown) tape loading members entered into the openings 102a.
FIG. 2(A) is a perspective view of the 8 mm tape cassette of the prior art and FIG. 2(B) is a side view for explaining a lid opening action of the 8 mm tape cassette.
On the other hand, the 8 mm tape cassette, 200 as shown in FIG. 2(A) and 2(B), has a construction substantially similar to the aforementioned one and is assembled of upper and lower half members 201 and 202 into a box-shaped casing, which is equipped therein with a supply reel 203 and a take-up reel 204 for causing the magnetic tape T to move. At an opening 202a provided on the lower half member 202 and at the back of a front lid 205, there is disposed a rear lid 206 for protecting the back face of the magnetic tape T, the side opposite to the magnetic tape.
This 8 mm tape cassette 200 is disclosed in the Japanese Laid-Open Patent Publication No. 168979/1984. Here will be briefly described in the vicinity of the front lid 205 and the rear lid 206. Along the front lid 205 which is disposed at the side of the opening 202a of the lower half member 202, there is guided the magnetic tape T which is protected while being interposed between the front lid 205 and the rear lid 206.
Specifically, the front lid 205 is so supported at the right-hand and left-hand sides of the upper and lower half members 201 and 202 that it can be freely opened or closed on a pair of pins 205a and 205a formed integrally with the inner walls of the right-hand and left-hand sides thereof. From the middle portion of the front lid 205, on the other hand, there concurrently depend a pair of projections 205b and 205b, which rotatably support the generally "T-shaped" rear lid 206 such that the rear lid 206 can rotate by means of a pair of pins 206a and 206a integrated therewith.
From the lower ends of the right-hand and left-hand sides of the rear lid 206, there are concurrently projected a pair of guide pins 206b and 206b. These guide pins 206b and 206b are fitted in a pair of guide grooves 202b and 202b which are formed in the right-hand and left-hand sides of the opening 202a of the lower half member 202.
Only when a not-shown magnetic recording and/or reproducing apparatus is loaded with the 8 mm tape cassette 200, as shown in FIG. 2(B), the front lid 205 and the rear lid 206 are opened together by a lid opening device of the apparatus, rotating around the supporting pins 205a formed on the front lid 205 which opens, as indicated by double-dotted lines.
Here, the rear lid 206 is opened concurrently and associatively with the opening action of the front lid 205 to a position of a large open angle .theta..sub.2 above the upper face 201a of the upper half member 201. In this moment, the rear lid 206 is opened upward on its pins 206a, with the guide pins 206b guided in the guide grooves 202b formed in the lower half member 202.
In recent years, the magnetic tape T is required to undergo the recording and/or reproducing operations in a high density with excellent performance quality. At the present stage, moreover, the recording and playing operations can be digitally effected, the recording and/or reproducing qualities are apt to be seriously deteriorated if the magnetic tape T becomes dusty or is stained with fingerprints.
In the aforementioned VHS tape cassette 100, the magnetic tape T does not have its magnetic face and opposite back face being physically protected. As a result, if the magnetic tape T has its back face contaminated with dust coming from the openings 102a or erroneously or accidentally stained with the fingerprints through the openings 102a, its back face may come into close contact with its magnetic face to cause malfunctions when it is wound on the supply reel 103 or the take-up reel 104.
It is, therefore, considered that a member corresponding to the disclosed rear lid (206) of the aforementioned 8 mm tape cassette 200 is attached to the VHS tape cassette 100. However, the not-shown magnetic recording and/or reproducing apparatus adopting the VHS tape cassette 100 has already been widely used in the relevant field. Considering the interchangeability between the VHS tape cassette 100 and the apparatus, the following problems (1) and (2) will arise to the users seriously, if the construction of the 8 mm tape cassette 200 is applied to the VHS tape cassette 100 as it is. Thus, it is difficult to adopt the member corresponding to the rear lid (206) into the existing construction.
(1) In the apparatus of the type such as a portable video deck or a video movie, the front lid has its open angle designed to the minimum so as to reduce the size. In case, therefore, the member corresponding to the rear lid (206) of the aforementioned construction of the 8 mm tape cassette 200 adopted, that member can not be opened sufficiently and will collide with the tape loading members for extracting the magnetic tape T into the apparatus.
(2) In the apparatus of the type such as a large-sized video deck or a video deck for professional use, on the other hand, the open angle of the front lid is designed to a sufficient value. In case, therefore, the member corresponding to the rear lid (206) of the construction of the aforementioned 8 mm tape cassette 200, the guide pins (2O6b, 206b) of the member corresponding to the rear lid (206) will come upward out of the guide grooves (202b, 202b) and be damaged when the member corresponding to the rear lid (206) is closed.
In short, the rear lid opening/closing structure associated with the front lid has to be reliably applicable in its basic construction not only to the apparatus having a large front lid open angle but also to the apparatus having a small front lid open angle, no matter how much its external shape might be different. Thus, there has been desired a tape cassette which can satisfy that condition.